"It's a debate that is obviously worth having. But you can't generalise against violence against women on television because it's got to be seen on its own merit," he said.

The fourth episode in the series, which was shown on BBC One, saw kidnapper Tommy Lee Royce - played by James Norton - assaulting police sergeant Catherine Cawood, played by Sarah Lancashire, and leaving her for dead.

Steve continued: "I think what Sally did was incredibly responsible. This crime of violence against women does exist, and I don't think it was used for cheap effect. It has got the debate out there and I don't think it was done for titillation or purely for excitement purposes."

He added: "It was really well handled. I know everyone is sensitive about it. Sally knew what she wanted to do and the effect she wanted to create."

Happy Valley, which ended its run on screens on June 3, is doing well in the pre-orders chart. It will be available on DVD from June 16.

"When I read the script, I saw it was such a strong piece and the characters were well drawn. It was done on a big scale and nothing is in black and white," Steve said.

"It's still a real surprise that it has taken off the way that it has. There's a lot of good quality drama out there but this has captured people's imaginations. Between Sally and Sarah, the rest of us were proud to be a part of it."